It is well established in the art to produce hard and soft contact lenses in an automated production process with reusable moulds. In mass production of contact lenses, specifically so-called disposable lenses, a large number of contact lenses must be manufactured in a relatively short period of time. In an advantageous method of mass production, a starting material, e.g., a prepolymer solution containing water, is introduced into a female mould half, the casting mould is closed by the respective male mould half and then the starting material is polymerized and/or crosslinked with ultraviolet (UV) light. The mould halves mask the UV light in the respective areas which are outside of the areas required for contact lens production. Such cyclic mass production of contact lenses is described, e.g., in WO 98/42497. Suitable polymers formed by photochemical polymerization of suitable prepolymers include polymers based on polyvinyl alcohols (PVA) or silicone hydrogels (SiHy) as well as based on polyethylene glycols (PEG).
Besides casting and polymerization and/or crosslinking of the contact lenses the production process comprises a treatment of the contact lenses in a number of further treatment stations, such as, e.g., a coating station, a cleaning station, or an inspection station. To ensure the quality of the contact lenses in an automated production process, the finished contact lenses must be optically inspected. However, contact lenses, in particular soft contact lenses, are difficult to handle using mechanical means. Therefore, in the inspection station, for example, the contact lenses are individually inserted into water filled cuvettes for the purpose of optical testing. Such a cuvette for optical testing of contact lenses is known, e.g., from WO 2007/042280. Removal of a contact lenses from such a water filled cuvette, hither-to is accomplished by introducing a suction tube into the cuvette. Due to an underpressure applied through the suction tube the contact lens is removed from the cuvette together at least with some of the water contained therein. The problem with this technology lies in the fact that it requires a considerable technical effort for the removal of the contact lens and the water from the vacuum system. For that purpose special vacuum separators are required which are complicated, costly and require specific maintenance. The application of vacuum also is limited to a theoretical maximum pressure difference of about 1 bar. Practically, the achievable maximum pressure difference lies in the range of about 0.5 bar only. This small pressure difference may result in a suction power which is too little, such that not every contact lens is removed from its respective cuvette.
It is therefore an object of the present invention to provide a method and a device for the removal of contact lenses from containers, such as, e.g., inspection cuvettes, which overcomes the above-mentioned drawbacks. A method and a device shall be provided which ensures the removal of contact lenses from the containers. Complicated and costly vacuum separators shall be avoided.